1. Field of Invention
This invention relates to the re-surfacing of concrete. More particularly, it relates to an apparatus having utility in resurfacing concrete found in vertical walls such as cooling towers.
2. Description of the Prior Art
Cooling towers are huge structures having concrete walls of hyperbolic shape. The shape creates an upwardly flowing draft of air that cools heated cooling water from steam condenser boxes that convert hot steam back into condensate water that is re-heated and re-used as steam. The concrete walls require refinishing from time to time. The art currently requires the building of scaffolding that carries workers to the top of the tower and which gradually lowers the workers as they remove the concrete with jack hammers and other equipment.
There are a number of drawbacks to the known concrete-removal procedure. Scaffolding is inherently dangerous, for example. Moreover, the work is labor intensive and the time required to remove the concrete is substantial. Jack hammers inherently leave micro fractured concrete behind, creating a very poor surface to which repair concrete may adhere. This leads to premature failure of the repaired concrete.
There is a need for a procedure that does not require workers to stand on an elevated scaffold. There is also a need for a procedure that performs the work in substantially less time and which does not create poor concrete bonding surfaces.
However, in view of the art considered as a whole at the time the invention was made, it was not obvious to those of ordinary skill in this art how the concrete-removing procedure could be improved. The non-obviousness of the invention disclosed below is established by the many years that the art has employed workers on scaffolds to do the job.